Breakthrough in Mpox Treatment: Human Antibodies Offer New Hope

Researchers from Mount Sinai's Microbiology Department have identified three powerful human monoclonal antibodies targeting the mpox virus, also known as monkeypox. These antibodies specifically recognize the viral protein A35, which is essential for the virus's spread. Laboratory tests demonstrated that these antibodies can effectively block the virus from spreading, protect animal models from severe disease, and prevent death. This discovery, published in the journal Cell, reveals that individuals previously infected with mpox carry high levels of these protective antibodies, which correlate with milder symptoms and no hospitalization.

Mpox is caused by an orthopoxvirus related to smallpox, spread mainly through close contact, causing painful rashes, lymph node swelling, fever, and potential scarring. Despite a significant outbreak starting in 2022 and declarations of public health emergencies by WHO, effective treatments remain scarce. Current clinical trials of leading therapies have not demonstrated efficacy, highlighting the urgent need for new options.

The newly identified antibodies target a highly conserved region of A35 shared across the entire poxvirus family, making them resistant to mutations and unlikely to be evaded by viral changes. Their ability to neutralize the virus and prevent severe outcomes positions these antibodies as promising candidates for future therapies. The research team has patented these antibodies and is progressing toward advanced preclinical testing.

This study is notable for providing the first crystal structure of a human antibody bound to an mpox viral protein, mapping a key vulnerability in the virus. It also marks the first quantification of monoclonal antibodies against orthopoxviruses in human sera, showing consistent immune responses among recovered patients.

While promising, further research, including clinical trials, is necessary to evaluate how these antibodies behave in humans, their durability, biodistribution, and efficacy in preventing infection. The team aims to advance these antibodies into safety and efficacy testing, advancing the fight against mpox and related viruses.

The study was conducted by Mount Sinai's Department of Microbiology, including researchers Coelho, Schotsaert, Simon, Bajic, and Krammer. This breakthrough could herald a new era of targeted immunotherapies for orthopoxviruses.

Source: https://medicalxpress.com/news/2025-08-potent-human-antibodies-mpox-pave.html